There are many reasons that the Keystone XL pipeline will clearly exacerbate the problem of climate pollution…but one that is often overlooked (at our peril) is theproblem of petroleum coke (aka “petcoke”). Petcoke is a refining byproduct of tar sands oil, and when burned is substantially dirtier than coal and contributes significantly to greenhouse gas pollution.

Read below to see just how significant Keystone XL’s petcoke problem would be…with enough petcoke to add emissions equivalent to 3.5 million additional cars each year, the question of whether Keystone XL’s climate impact is “significant” becomes an easy one to answer.